Discovery Rupes' Scarp (HR)

A limping Mariner 10 spacecraft was coaxed into a third and final encounter with Mercury in March of 1975.
Due to several problems with the aging spacecraft, only ~450 useful images of the Planet were acquired, though many are at significantly higher resolution than previous encounters.

In this HR image (FDS 528884) the Sun is low to the horizon thus enhancing topographic features with prominent shadows.
As can be seen here, the surface of Mercury is heavily cratered similar to the Moon.